How Contact Lenses Are Contributing To Microplastic Pollution

By tallying this detritus and studying how it persists in this environment, the study provides the first estimate of the potential burden of these tiny plastics, or microplastics.

It's important to keep the findings in perspective; Halden points out that contacts make up a "very, very small fraction" of the plastics that ultimately wind up in the ocean, and serve a far more useful objective than "frivolous" plastics like single-use bags and straws. Halden mentions, "Ultimately, we hope that manufacturers will conduct more research on how the lenses impact aquatic life and how fast the lenses degrade in a marine environment".

That failure to break down led the researchers to a startling conclusion: as much as 23,000 kilograms of lenses (about 50,000 pounds) may accumulate in sewage sludge in the USA each year.

"This began as an exploratory venture but we have information to support the fragmentation of contact lenses into microplastics within a wastewater treatment plant", said Charles Rolsky, one of the study's authors and a graduate student at ASU.

Of an estimated 45 million USA contact lens wearers, that's around 9 million right there.

"We were concerned with what happens to those contact lenses once they're exposed to the processes in the waste water treatment plant", Rolsky says.

The team sifted through wastewater sludge, and found several fragments of contact lenses, which indicated that wastewater processing doesn't just let the lenses through - it also appears to help them break into smaller bits.

A study by Arizona State University says the plastic ends up in waste water treatment plants.

Big data on wastewater is largely unavailable, and quantifying the mass of microplastics is challenging, says Sherri Mason, a professor of chemistry at the State University of NY at Fredonia.

The researchers broke the study into three core parts.

And those lenses later end up contributing to pollution in oceans, lakes and rivers. Or they could sit in soil, desiccating in the sun.

"If you think of plastic pollution, contact lenses are not the first thing that come to mind", says Rolf Halden, director of the Biodesign Center for Environmental Health Engineering at Arizona State University. "Once these lenses dry, they become incredibly brittle and will very likely shatter into very small particles". These animals are part of a long food chain.

"Contacts are created to absorb liquid, and that includes not just water but anything that's in the water", Mason says.

However, they say it's one problem that can be easily addressed by making people aware of some of the staggering numbers related to their disposal.

If filter feeders and small fish ingest the contacts, whether whole or shattered, it could cause a blockage in their bodily functions. The team concluded that microbes in the wastewater treatment facility actually altered the surface of the contact lenses, weakening the bonds in the plastic polymers. "And because that's not providing nutrients, it is possible for organisms like that to starve", Rolsky says. "Everyone should have an incentive to avoid plastic pollution".

And if you've ever flushed your used lenses, and are reading this? Of the lens wearers, 19 percent admitted to flushing their lenses down the drain or toilet.